An 8-year old Iowa boy was kept in what authorities have described as "a dungeon" under the basement stairs, without light, food or bedding for hours at a time.

The boy was given a tin can to urinate in, but often had to sleep in or near his own urine, police say.

The boy's father, Alex Craig Shadlow, 30, has been arrested and charged with first-degree kidnapping after police say he physically and mentally abused the young boy. His girlfriend, Traci Lynn Tyler, 39, also faces first-degree kidnapping charges, according to the Des Moines Register.

The couple is accused of keeping the boy locked in a 6-foot-by-6-foot area underneath the basement stairs for at least nine hours each day between July and September 2017, the Associated Press reported.

Ackley Police Chief Brian Shimon described the space as "a dungeon," while Hardin County Attorney Darrell Meyer described it as "a coffin," according to the Des Moines Register.

Authorities say there was no light in the small enclosure and the boy was often forced to sleep on a cement floor, without a pillow, blanket or mattress.

The boy also bore permanent scars on his back and limbs, after officials say in court records that Tyler allegedly hit him with the handle of a flyswatter and encouraged their dog to bite him.

The Iowa Department of Human Services began investigating the case after the boy told one of his teachers he was being locked in the basement every day after school. Teachers at the school had become suspicious of the boy's home life, after noticing he was often hungry, had a low body weight and had his hair falling out in patches.

His teachers at school described the boy as a good student who was well behaved, but quiet, according to The Register.

The Iowa Department of Human Services made a surprise visit to the house and was able to document and photograph the basement enclosure, which even included a makeshift door, the Waterloo Courier reported.

Tyler allegedly told authorities they had locked the boy in the space because of bad behavior and stealing food, court documents say.

Shadlow's sister, Jessica Shadlow, told the Des Moines Register her brother's alleged behavior did not match the person she knew.

"He loved his son. His son was everything to him," she told the paper.

She blamed the shift in his behavior on his relationship with Tyler and told the paper Tyler called the child stupid and yelled at him in the past. Eventually, the couple stopped allowing Jessica Shadlow's mother into the home, she said.

She told the paper her family is now furious with Alex Shadlow for the alleged abuse of the boy.

"I had nightmares last night about it," she told the paper. "About him sitting in a little dark space all by himself, not being able to see anything."

Although online court records don't show any abuse-related convictions in Iowa for Tyler or Shadlow, the police had been to the home several times in the past, according to The Register.

Police records show an officer was sent to the house after receiving a call that the boy was being forced to carry weights around in circles in the garage. The officer spoke to the boy and gave him several slices of pizza to eat, but the county's attorney's office didn't think at the time the punishment was abuse.

Shimon had also visited the residence in the past after the boy had been forced to sleep outside in the pouring rain. He reported the incident to the Iowa Department of Human Services, according to The Register.

The couple are each being held on $500,000 bond, according to The Courier. They could face life in prison if convicted of the first-degree kidnapping charges.